Of 52,757 HD patients in Taiwan’s National Health Insurance Research Database during 2001 to 2009, 8151 received oral calcitriol or alfacalcidol (intravenous medication is not reimbursable). Vitamin D users had lower all-cause mortality than nonusers over a median 3 years of follow-up: 9 vs 13 per 100 person-years, Yea-Huei Kao Yang, MD, of National Cheng Kung University, and colleagues reported in BMC Nephrology. Multivariate analysis and propensity score matching analysis found that active vitamin D therapy was associated with a significant 9% and 6% decreased mortality risk, respectively. Adjustments were made for age, sex, vascular access type, comorbidities, and medications.

The investigators considered the influence of vitamin D doses. Most patients received a median 110 dosage units (25 µg per unit) and the remainder received greater dosage units (median 805 dosage units). High-dose vitamin D recipients had a significant 25% lower risk of death than conventional-dose recipients. Analyses of vitamin D usage after 6 months and 1 year of dialysis initiation provided similar results.

Secondary hyperparathyroidism and vitamin D deficiency are considered partly to blame for excess mortality in HD patients.

“There was no excess risk for death in patients receiving higher doses of vitamin D. Therefore, our data supports the prescription of activated vitamin D in these patients unless contraindicated,” Dr Yang and his colleagues stated.

“Reducing use of calcium-based phosphate binders should be considered to trade off for more activated vitamin D prescriptions to avoid the risk of hypercalcemia, inadequately suppressed PTH levels, or low bone turnover disease,” they added.

The investigators used a landmark study design to reduce immortal time bias. One study limitation is the lack of relevant laboratory data in the database, such as calcium, phosphorus, parathyroid hormone, and hemoglobin concentrations, smoking status, and markers of inflammatory status.